Antistatic compositions comprising polymerized oxyalkylene monomers and an inorganic tetrafluoroborate, perfluoroalkyl carboxylate, hexafluorophosphate or perfluoroalkylsulfonate salt

ABSTRACT

Antistatic compositions are disclosed comprising a hydrophilic binder, surface-active polymer having polymerized oxyalkylene monomers and an inorganic salt characterized in that the salt is selected from the group consisting of inorganic tetrafluoroborates, perfluoroalkyl carboxylates, hexafluorophosphates and perfluoroalkyl sulfonates.

FIELD OF THE INVENTION

The present invention relates to antistatic compositions and elements,including photographic elements. More specifically, the presentinvention relates to antistatic compositions comprising polymerizedoxyalkylene monomers and inorganic salts and the use of suchcompositions as antistatic layers.

BACKGROUND OF THE INVENTION

The unwanted build-up of static electricity on an insulated support iswell known. This phenomenon occurs on any element having an electricallyinsulating support surface.

In photographic elements, including electrophotographic elements,radiation-sensitive emulsions are usually coated on an insulatingsupport. It has been a practice to reduce the electrostatic chargebuild-up by coating the surface of the support on which no photographicemulsions are coated with an antistatic composition. Sometimes aphotographic emulsion layer is also coated with antistatic compositions.Such antistatic compositions decrease the surface resistivity therebypreventing the accumulation of electrical charges.

In U.S. Pat. No. 4,272,616 a homogeneous antistatic compositioncomprising a hydrophilic binder, such as gelatin, containing a nonionicpolyoxyethylene surface-active agent and an alkali metal thiocyanate,iodide, perchlorate or periodate is disclosed. Such antistaticcompositions are effective in reducing the surface resistivity of suchsupports to about 10¹¹ ohms/sq at 30% relative humidity (RH). Theproblem is that such antistatics are not compatible with allphotographic elements or the manufacture of such elements. Some of thealkali metal salts used therein have an adverse effect on someradiation-sensitive photographic emulsions. Other such salts, such asthe perchlorates, are known to be explosive, thus producing amanufacturing hazard. The purpose of the present invention is to providenovel alternative antistatic compositions which have none of the abovedrawbacks of the above prior art salts.

SUMMARY OF THE INVENTION

The present invention provides an antistatic composition comprising abinder, a surface-active polymer having polymerized oxyalkylene monomersand an inorganic salt characterized in that the salt is selected fromthe group consisting of inorganic tetrafluoroborates, perfluoroalkylcarboxylate, hexafluorophosphate and perfluoroalkyl sulfonates.

Such compositions, when coated on insulating surfaces, reduce thesurface resistivity of emulsion layers and supports as much as fiveorders of magnitude at 20% relative humidity. Moreover, suchcompositions do not cause the adverse effects on someradiation-sensitive emulsions or present the manufacturing problem ofthe above prior art compositions.

The alkylene portion of the oxyalkylene monomer refers to divalenthydrocarbon groups having 2 to 6 carbon atoms such as ethylene,propylene and butylene.

In one aspect, the present invention provides antistatic compositionswherein the oxyalkylene monomer is selected from the group consisting ofoxyethylene and oxypropylene and the salt is selected from the groupconsisting of alkali metal tetrafluoroborates, alkali metaltrifluoromethanesulfonates, alkali metal trifluoroacetates, alkali metalperfluorobutanoates, alkali metal hexafluorophosphates and alkali metalperfluorobutanesulfonates.

In another aspect, the present invention provides elements, includingphotographic elements, comprising layers of the antistatic compositionsof this invention.

DETAILS OF THE INVENTION

The antistatic compositions of the present invention are generallyprepared by combining the binder with an aqueous solution of thesurface-active polymer containing the polymerized alkylene oxidemonomers and an aqueous solution of the selected inorganic salt. Theresulting antistatic composition can be coated on insulating supports toreduce the resistivity of the support.

The binder is generally present in the composition, on a dry basis, inan amount of from 10 to 95 weight percent. Useful binders for formingthe antistatic compositions are selected from the many knownphotographically useful hydrophilic colloid compositions. Suitablehydrophilic colloids include both naturally occurring substances such asproteins, protein derivatives, cellulose derivatives, e.g. celluloseesters, gelatin, e.g. alkali-treated gelatin (cattle bone or hidegelatin) or acid-treated gelatin (pigskin gelatin), gelatin derivatives,e.g. acetylated gelatin, phthalated gelatin and the like,polysaccharides such as dextran, gum arabic, zein, casein, pectin,collagen derivatives, collodion, agar-agar, arrowroot, albumin and thelike as described in numerous patents relating to the photographic arts.

Other hydrophilic colloids include colloidal albumin or casein, etc.;cellulose compounds such as carboxymethyl cellulose or hydroxyethylcellulose, etc.; and synthetic hydrophilic colloids such as polyvinylalcohol, poly-N-vinylpyrrolidone, polyacrylic acid copolymers,polyacrylamide or derivatives of them or partially hydrolyzed productsof them, etc. If necessary, mixtures of two or more of these colloidsare used. Among them, the most useful one is gelatin. The gelatin usedhere includes the so-called lime treated gelatin, acid treated gelatinand enzyme treated gelatin.

The surface-active polymers are generally present in the composition, ona dry basis, in an amount from 2 to 80 weight percent. Anysurface-active polymer including homopolymers and copolymers andpolymerized oxyalkylene monomers will be useful. Useful co-monomersinclude alkyl siloxane monomers and vinyl monomers as illustrated inTable I infra. Useful surface-active polymers containing blocks ofpolymerized oxyalkylene monomers are disclosed in U.S. Pat. Nos.2,917,480, 4,272,616, 4,047,958 and Japanese Patent Applications Nos.55/70837 and 52/16224. Some preferred polymers containing polymerizedblocks of oxyalkylene are presented in Table I.

                  TABLE I                                                         ______________________________________                                        (1)  Block copolymers of propylene oxide and ethylene                              oxide available from BASF under the name                                      Pluronic ®, e.g. Pluronic ® P123 and                                  Pluronics ® 25R5:                                                          ##STR1##                                                                     a plus c = 10 to 270                                                          b = 20 to 70                                                                  or                                                                             ##STR2##                                                                     wherein d plus f = 10 to 160 and                                              e = 15 to 60.                                                            (2)  Tetrafunctional block copolymers derived from the                             addition of ethylene oxide and propylene oxide to                             ethylene diamine available from BASF under the                                name Tetronics ®, e.g. Tetronics ® T1304:                         ##STR3##                                                                           ##STR4##                                                                (3)  Polyethoxylated derivatives of castor oil avail-                              able from BASF under the name Industrol ® CO,                             e.g. Industrol ® CO-40:                                                    ##STR5##                                                                      ##STR6##                                                                (4)  Polyethoxylated ether derivatives of alkyl sub-                               stituted acetylenic diols available from Air                                  Products Co. under the name Surfynol ®, e.g.                              Surfynol ® 465:                                                            ##STR7##                                                                     wherein g plus h = 10 to 30.                                             (5)  Dimethylsiloxane-alkylene oxide linear BAB block                              copolymers available from Dow Corning under the                               trade name Q4-3667 ®:                                                      ##STR8##                                                                      ##STR9##                                                                      ##STR10##                                                               (6)  Polyoxyethylene(20) sorbitan monolaurate avail-                               able from ICI of America under the trade name                                 Tween ® 20.                                                          (7)  Polyoxyethylene perfluorodecenyl ether available                              from ICI of America under the name Monflor ®,                        51:  e.g. Monoflor ®                                                           CnF.sub.2n-1(CH.sub.2 CH.sub.2 O) .sub.mCnF.sub.2n-1                           ##STR11##                                                               (8)  Dimethylsiloxane-ethylene oxide block copolymers                              available from Petrarch Systems, Inc. under the                               name Petrarch ® PS, e.g. PS071 and PS073:                                  ##STR12##                                                                    wherein q/p = 1 to 5.                                                    (9)  Polyoxyethylene lauryl, cetyl, stearyl or oleyl                               ethers available from ICI of America under the                                trade name Brij ® Compounds.                                         (10) Polyalkylene oxide modified dimethylpolysiloxane                              branch chain copolymer available from Union                                   Carbide under the trade name Silwet, e.g.                                     Silwet ® L-7605:                                                           ##STR13##                                                                     ##STR14##                                                               (11) Alkyl or unsubstituted phenoxypoly(oxyethylene)-                              ethanol available from GAF under the trade name Igepal ®                  Compounds.                                                               (12) Octylphenoxypoly(oxyethylene)ethanol available                                from Rohm & Haas under the trade name Triton ®                            X-405.                                                                   (13) Ethoxylated fatty alcohol polyoxyethylene ethers                              available from Emery Industries under the trade                               name Trycol ® LAL Compounds.                                         (14) F(CF.sub.2 CF.sub.2) .sub.3-8CH.sub.2 CH.sub.2 O(CH.sub.2 CH.sub.2            O).sub.x H wherein x is 10                                                    to 20 available from DuPont under the trade name                              Zonyl ® FSN.                                                         ______________________________________                                    

The inorganic salt is generally present in the composition in an amountof from 2 to 80 weight percent. The inorganic salt is atetrafluoroborate, perfluoroalkyl carboxylate, hexafluorophosphate orperfluoroalkyl sulfonate. The alkyl group in perfluoroalkyl has 2 to 20carbon atoms. Alkali and alkaline earth metals and ammonium salts ofsuch materials are examples of useful inorganic salts. Examples ofalkali metals include potassium, sodium, lithium, cesium and rubidium.Examples of alkaline earth metals are beryllium, calcium, strontium andbarium. Some preferred salts are CF₃ SO₃ K, LiBF₄, NaBF₄, C₄ F₉ SO₃ K,C₃ F₇ COOK, KPF₆ and CF₃ SO₃ Li.

Coated layers of the antistatic composition should include sufficientpolyoxyalkylene surface-active agents and inorganic salts to exhibit theantistatic effect. A preferred amount of the polyoxyalkylenesurface-active agent is in the range of about 5 to 500 mg/m² andparticularly about 20 to 200 mg/m². A preferred amount of the salt usedtogether therewith is in the range of about 5 to 500 mg/m² andparticularly about 10 to 200 mg/m². Binder coverage should be in therange of 0.1 to 10 g/m². Of course, the above-described ranges varyaccording to the type of the photographic film base, photographiccomposition, form or application method used. A suitable ratio for theamount of polyoxyalkylene compound to salt is about 1:0.1 to 5.0 andpreferably about 1:0.3 to 2 by weight.

The compositions can be coated on a wide variety of supports to form awide variety of useful antistatic elements. The support can be a numberof materials which can take a number of forms. For example, thecompositions can be coated on polymeric materials such as poly(ethyleneterephthalate), cellulose acetate, polystyrene, poly(methylmethacrylate) and the like. The compositions can also be coated on othersupports such as glass, paper including resin-coated paper, and metals.Fibers including synthetic fibers, useful for weaving into cloth, can beused as the support. Planar supports such as polymeric films useful inphotography are particularly useful. In addition, the compositions ofthe present invention can be coated onto virtually any article where itis desired to decrease resistivity. For example, the compositions can becoated on small plastic parts to prevent the unwanted buildup of staticelectricity or coated on small polymeric spheres or other shapes such asthose used for toners in electrography and the like.

The compositions of the present invention can be applied to the supportusing any suitable method. For example, the compositions can be coatedby spray coating, fluidized bed coating, dip coating, doctor bladecoating or extrusion hopper coating, to mention but a few.

In some embodiments, it may be desirable to coat the layer of theantistatic compositions of the present invention with a protectivelayer. The protective layer can be present for a variety of reasons. Forexample, the protective layer can be an abrasion-resistant layer or alayer which provides other desirable physical properties. In manyembodiments, for example, it can be desirable to protect the layers ofthe antistatic composition from conditions which could cause theleaching of one of the components. Where the antistatic layer of thepresent invention is part of an element having a basic layer, it can bedesirable to provide a barrier in the form of a protective layer toprevent the contact of the antistatic layer by base. The protectivelayer is preferably a film-forming polymer which can be applied usingcoating techniques such as those described above for the conductivelayer itself. Suitable film-forming resins include cellulose acetate,cellulose acetate butyrate, poly(methyl methacrylate), polyesters,polycarbonates and the like.

The coating compositions of the present invention are particularlyuseful in forming antistatic layers for photographic elements. Elementsof this type comprise a support having coated thereon at least oneradiation-sensitive layer. Layers of the antistatic composition can bein any position in the photographic element. The antistatic compositionsare advantageously coated directly on the support which can have a thinsubbing layer as is known in the art, and are then overcoated with thedescribed protective layer. Alternatively, the antistatic layers can beon the same side of the support as the radiation-sensitive materials andthe protective layers can be included as interlayers or overcoats, ifdesired.

The radiation-sensitive layers of the photographic orelectrophotographic elements can take a wide variety of forms. Thelayers can comprise photographic silver salt emulsions, such as silverhalide emulsions; diazo-type compositions; vesicular image-formingcompositions; photopolymerizable compositions; electrophotographiccompositions comprising radiation-sensitive semiconductors; and thelike. Photographic silver halide emulsions including, but not limitedto, single or multilayer, black-and-white or color, with or withoutincorporated couplers are particularly preferred and are described, forexample, in Research Disclosure, Item 17643 (Silver Halide Elements),December 1978, pages 22-31 and Research Disclosure, Item 18431(Radiographic Elements), August 1979, pages 433-41.

By practicing the present invention, the problems caused by staticcharges generated in production and use are significantly diminished.For example, the occurrence of static marks caused by contact betweenthe emulsion face and the back face of the photographic sensitivematerial, contact of one emulsion face with another emulsion face andcontact of the photographic sensitive material with other materials suchas rubber, metal, plastics and fluorescent intensifying screens isremarkably reduced by practicing the present invention. Further, surfaceresistivity of the photographic sensitive materials remarkably decreaseswhen the salts and polyoxyalkylene compounds in the present inventionare used together in a hydrophilic binder and applied to the outsidelayer of the photographic sensitive materials.

Moreover, the combinations of compounds used in the present inventioneffectively prevent the static charges generated in placing films incassettes or loading films in cameras or in taking many photographscontinuously at a high speed by an automatic camera. The antistaticeffect does not deteriorate with the lapse of time or low humidity.

The present invention is now illustrated in more detail by reference tothe following examples. However, the present invention is not to beconstrued as being limited to these examples.

The resistance of the surface of the coatings of the present inventioncan be measured using well-known techniques.The resistivity is theelectrical resistance of a square of a thin film of material measured inthe plane of the material between opposite sides. This is described morefully in R. E. Atchison, Aust. J. Appl. Sci., 10, (1954).

The following examples are presented to further clarify the invention.

EXAMPLE 1

Single Layer Coatings

A layer of deionized bone gelatin was coated on a polyester support at alevel of 0.097 g/m² (Example 1A). Additions of surface-active polymershaving polymerized oxyalkylene monomers and of salts were made (Examples1B-1U) as listed in Table I, and at the levels (mg/m² of coating)indicated.

Samples of the coatings were conditioned to 50%, 20% and/or 15% relativehumidity. The surface resistivity was measured at 24° C. using a KeithlyPicoammeter, according to the procedure of ASTM Standard D-257. Theresults are tabulated in Table II.

                                      TABLE II                                    __________________________________________________________________________    Single Layer Gelatin Coatings                                                                       Coverage,                                                                              Surface Resistivity                            Example                                                                            Table I          mg/m.sup.2                                                                             Ohms/Square                                    No.  Polymer   Salt   Polymer                                                                            Salt                                                                              50% RH                                                                              20% RH 15% RH Comments                   __________________________________________________________________________    1A   none      none    0    0    2 × 10.sup.14                                                               >2 × 10.sup.15                                                                 --     Control                    1B   10        none   160   0  6.3 × 10.sup.12                                                               9.5 × 10.sup.13                                                                --     Polymer                         (Silwet L7605)                                alone                      1C   none      CF.sub.3 SO.sub.3 K                                                                   0   160   1 × 10.sup.13                                                               6.3 × 10.sup.14                                                                --     Salt alone                 1D   10        CF.sub.3 SO.sub.3 K                                                                  129  32    2 × 10.sup.9                                                                4 × 10.sup.9                                                                   --     Invention,                                                                    high level                                                                    salt                       1E   10        CF.sub.3 SO.sub.3 K                                                                   65  16  6.3 × 10.sup.9                                                                1.3 × 10.sup.10                                                                --     Invention,                                                                    medium                                                                        level salt                 1F   10        CF.sub.3 SO.sub.3 K                                                                   32   9    3 × 10.sup.10                                                               5 × 10.sup.10                                                                  --     Invention,                                                                    low level                                                                     salt                       1G   10        C.sub.4 F.sub.9 SO.sub.3 K                                                           140  22  9.5 × 10.sup.9                                                                1 × 10.sup.10                                                                  --     Invention                  1H   10        C.sub.3 F.sub.7 COOK                                                                 140  22  2.5 × 10.sup.9                                                                1 × 10.sup.10                                                                  --     Invention                  1I   10        CF.sub.3 COOK                                                                         81  102   2 × 10.sup.9                                                                3 × 10.sup.10                                                                  --     Invention                  1J    1        LiBF.sub.4                                                                           160  160   1 × 10.sup.10                                                               4 × 10.sup.10                                                                  --     Invention                       (Pluronic ® P123)                                                    1K   1         CF.sub.3 SO.sub.3 K                                                                  129  32    3 × 10.sup. 10                                                              --     9.5 × 10.sup.10                                                                Invention                  1L   5         CF.sub.3 SO.sub.3 K                                                                  129  32  9.5 × 10.sup.9                                                                --     2 × 10.sup.10                                                                  Invention                       (Q4-3667)                                                                1M   5         CF.sub.3 SO.sub.3 K                                                                  160  160   1 × 10.sup.10                                                               2.5 × 10.sup.10                                                                --     Invention                  1N   4         CF.sub.3 SO.sub.3 K                                                                  81   81  --    --     1 × 10.sup.10                                                                  Invention                       (Surfynol ® 485)                                                     1O   4         CF.sub.3 SO.sub.3 K                                                                  81   81  --    --     1.3 × 10.sup.10                                                                Invention                       (Surfynol ® 465)                                                     1P   1         CF.sub.3 SO.sub.3 K                                                                  81   81  --    --     2 × 10.sup.10                                                                  Invention                       (Pluronic ® F87)                                                     1Q   1         CF.sub.3 SO.sub.3 K                                                                  81   81  --    --     1.6 × 10.sup.10                                                                Invention                       (Pluronic ® 10R5)                                                    1R   2         CF.sub.3 SO.sub.3 Li                                                                 81   81  --    1 × 10.sup.11                                                                  --     Invention                       (Tetronic ® T-1304)                                                  1S   8         CF.sub.3 SO.sub.3 Li                                                                 81   81  --    6.3 × 10.sup.10                                                                --     Invention                       (Petrarch ® PS073)                                                   1T   8         CF.sub.3 SO.sub.3 Li                                                                 81   81  --    2.5 × 10.sup.10                                                                --     Invention                       (Petrarch ® PS197)                                                   __________________________________________________________________________

As compared to the control Example 1A, Example 1B and 1C showsignificant reductions in surface sensitivity when the surface-activepolymer or the salt are added separately. However, the combination ofsalt and polymer of this invention in Example 1D shows a much greater,synergistic reduction in surface resistivity of five orders of magnitudeat 50% RH, and even more at 20% RH. This effectiveness is largelyretained even at the lower addenda levels of Examples 1E and 1F.Examples 1F-1U illustrate the similar reductions in surface resistivityprovided by other polymer and salt combinations of the invention.

EXAMPLE 2

Medical X-ray Film Coatings

A radiographic emulsion layer was coated on a polyester support at alevel of 2.37 gm Ag/m² and 1.51 gm gelatin/m². The emulsion comprisedcubic silver bromoiodide grains of 0.9 μm mean size, and 4 mole percentiodide. The emulsion layer also contained KNO₃ at 129 mg/m². Over theemulsion a protective layer was coated at a level of 0.65 g/m².Surface-active polymers and alkali metal salts were added to the latterovercoat as indicated in Table III. The surface resistivity wasdetermined at 50% and 20% relative humidity as described for Example 1except a Tera ohmmeter (Guidelines Instruments Model 9520) was used tomeasure resistivity. The results are tabulated in Table III. Reductionof this resistivity of three orders of magnitude or more are obtained at20% RH using the antistatic composition of this invention.

                                      TABLE III                                   __________________________________________________________________________    Radiographic Emulsion Overcoats                                                               Coverage,                                                                              Surface Resistivity                                  Example                                                                            Table I    mg/m.sup.2                                                                             Ohms/Square                                          No.  Polymer                                                                            Salt  Polymer                                                                            Salt                                                                              50% RH                                                                              20% RH                                                                              Comments                                 __________________________________________________________________________    2A   none none   0    0  5.4 × 10.sup.11                                                               >1 × 10.sup.13                                                                Control                                  2B   5    CF.sub.3 SO.sub.3 K                                                                 161  161 2.3 × 10.sup.10                                                               6.8 × 10.sup.10                                                               Invention                                     (Q4-3667)                                                                2C   5    CF.sub.3 SO.sub.3 K                                                                 161   81 2.2 × 10.sup.10                                                               6.2 × 10.sup.10                                                               Invention                                __________________________________________________________________________

EXAMPLE 3

Control Coating

On a polyester support was coated a layer of deionized bone gelatin at alevel of 2.71 g/m². Over this was applied a deionized bone gelatinovercoat at 0.89 g/m². The coating was hardened withbis(vinylsulfonylmethyl) ether at 2% of the total dry gelatin weight.The surface resistivity was measured as described in the previousexample.

Coating of the Invention

The coating of the invention was prepared as described for the controlcoating, except that 215 mg/m² each of polymer 10) of Table I (UnionCarbide Silwet® L7605) and of potassium hexafluorophosphate (KPF₆) wereadded to the overcoat layer. The resistivity was measured, giving thevalues tabulated below in Table IV.

                                      TABLE IV                                    __________________________________________________________________________    Coating                                                                              Table I   Coverage, mg/m.sup.2                                                                    Surface Resistivity                                No.    Polymer                                                                            Salt Polymer                                                                             Salt                                                                              50% RH                                                                              20% RH                                       __________________________________________________________________________    Control                                                                              --   --   --    --  5.3 × 10.sup.12                                                               >1 × 10.sup.13                         Example 3                                                                            10   KPF.sub.6                                                                          215   215 5.6 × 10.sup.10                                                               1.6 × 10.sup.11                        __________________________________________________________________________     The surface resistivity of the coating of the invention was greatly           reduced at both 50% and 20% RH.                                          

EXAMPLE 4

Sensitometric Effects of Salts of U.S. Pat. No. 4,272,616 Compared tothe Salts Used in the Present Invention

On a polyester support was coated a green-sensitized silver bromoiodidemedical x-ray emulsion of mean grain size 0.75 μm, containing 3.4 mole %iodide, at 1.9 g/m² Ag and 1.5 g/m² gelatin. Over the emulsion layer wascoated a protective layer containing 0.65 g/m² gelatin. Salts were addedto the emulsion layer as indicated in Table V, in each case at a levelof 1.08×10⁻³ moles/m².

Samples of the coatings were exposed through a graduated density scalefor 1/50 seconds to a 600-watt quartz halogen source filtered with aCorning® C-4010 filter to simulate a green-emitting fluorescent screenexposure. The samples were then processed in a KODAK X-OMAT® processor,Model M6. Development was for 26 seconds at 35° C., fixing for 21seconds at 35° C., and washing for 16 seconds at 32° C., using KODAK RPX-OMAT® Developer and Fix.

The sensitometric results are tabulated in Table V. The speed wasmeasured at a density of 1.0.

                  TABLE V                                                         ______________________________________                                        Coating Salt Added Relative                                                   No.     to Emulsion                                                                              Speed    Contrast                                                                             Fog   D.sub.max                            ______________________________________                                        Control none       100      2.80   .09   3.63                                 1       KI (prior art)                                                                            27      --     .02   2.16                                 2       CF.sub.3 SO.sub.3 Li                                                                     107      2.96   .02   3.65                                 3       NaBF.sub.4 110      3.02   .04   3.86                                 4       KPF.sub.6  105      2.88   .04   3.65                                 5       CF.sub.3 CO.sub.2 Na                                                                     102      3.05   .04   3.88                                 ______________________________________                                         Addition of prior art KI caused a large loss in speed, contrast and           D.sub.max. The contrast was too low to measure. On the contrary, addition     in Coating Nos. 2-5 of the salts used in the present invention caused no      adverse sensitometric effect.                                            

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

We claim:
 1. An element comprising a support and a layer of anantistatic composition comprising a hydrophilic binder, a surface-activepolymer having polymerized oxyalkylene monomers and an inorganic saltcharacterized in that the salt is selected from the group consisting ofinorganic tetrafluoroborates, perfluoroalkyl carboxylates,hexafluorophosphates and perfluoroalkyl sulfonates.
 2. A photographicelement comprising a support having thereon a radiation-sensitive layerand a layer of an antistatic composition comprising a hydrophilicbinder, a surface-active polymer having polymerized oxyalkylene monomersand an inorganic salt characterized in that the salt is selected fromthe group consisting of inorganic tetrafluoroborates,hexafluorophosphates, perfluoroalkyl carboxylates and perfluoroalkylsulfonates.
 3. The element of claim 1 or 2 wherein the oxyalkylenemonomer is selected from the group consisting of oxyethylene andoxypropylene and the salt is selected from the group consisting ofalkali metal perfluoromethanesulfonates, alkali metaltetrafluoroborates, alkali metal perfluoropropyl carboxylates, alkalimetal hexafluorophosphates and alkali metal perfluorobutanesulfonates.4. The element of claim 1 or 2 wherein the polymer is selected from thepolymers of Table I and the salt is selected from the group consistingof potassium trifluoromethanesulfonate, potassiumperfluorobutanesulfonate, potassium trifluoroacetate, potassiumperfluorobutanoate, lithium tetrafluoroborate, potassiumhexafluorophosphate and lithium trifluoromethanesulfonate.
 5. Theelement of claim 1 or 2 wherein the antistatic layer comprises from 5 to500 mg of polymerized polyoxyalkylene monomers per square meter of thelayer, from 5 to 500 mg of the inorganic salt per square meter and from0.1 to 10 gm of the binder per square meter.
 6. The element of claim 2wherein the photographic element is a radiographic element having asilver halide emulsion on each side of the support and wherein theantistatic layer overcoats each of the radiographic emulsions.
 7. Theelement of claim 2 wherein the antistatic composition is coated on thesupport surface which is remote from the radiation-sensitive layer.